Effects of roads on survival of San Clemente Island foxes

Nathan P. Snow, William F. Andelt, Thomas R. Stanley, Jessica R. Resnik, Linda Munson

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Roads generate a variety of influences on wildlife populations; however, little is known about the effects of roads on endemic wildlife on islands. Specifically, road-kills of island foxes (Urocyon littoralis) on San Clemente Island (SCI), Channel Islands, California, USA are a concern for resource managers. To determine the effects of roads on island foxes, we radiocollared foxes using a 3-tiered sampling design to represent the entire population in the study area, a sub-population near roads, and a sub-population away from roads on SCI. We examined annual survival rates using nest-survival models, causes of mortalities, and movements for each sample. We found the population had high annual survival (0.90), although survival declined with use of road habitat, particularly for intermediate-aged foxes. Foxes living near roads suffered lower annual survival (0.76), resulting from high frequencies of road-kills (7 of 11 mortalities). Foxes living away from roads had the highest annual survival (0.97). Road-kill was the most prominent cause of mortality detected on SCI, which we estimated as killing 3-8% of the population in the study area annually. Based on movements, we were unable to detect any responses by foxes that minimized their risks from roads. The probabilities of road-kills increased with use of the road habitat, volume of traffic, and decreasing road sinuosity. We recommend that managers should attempt to reduce road-kills by deterring or excluding foxes from entering roads, and attempting to modify behaviors of motorists to be vigilant for foxes.

Original languageEnglish (US)
Pages (from-to)243-252
Number of pages10
JournalJournal of Wildlife Management
Issue number2
StatePublished - Feb 2012


  • California Channel Islands
  • island fox
  • mortality
  • movement
  • road-kill
  • survival
  • Urocyon littoralis
  • vehicle

ASJC Scopus subject areas

  • Nature and Landscape Conservation
  • Ecology
  • Ecology, Evolution, Behavior and Systematics


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